1. Field of the Invention
The present invention relates to a substrate transfer robot, a substrate transfer system, and a method for transferring a substrate.
2. Discussion of the Background
Japanese Unexamined Patent Application Publication No. 2011-228627 discloses a substrate transfer robot with a hand capable of approaching a substrate storage on which a substrate (semiconductor wafer) is placed, in order to hold the substrate.
The substrate transfer robot disclosed in Japanese Unexamined Patent Application Publication No. 2011-228627 is a horizontally articulated substrate transfer robot including an arm and a hand. The arm is made up of a first arm and a second arm coupled in series to each other toward a distal end of the arm. The hand is coupled to the distal end of the arm. The substrate transfer robot is fixed in a robot installment area and takes a substrate into and out of a plurality of substrate storages (substrate storage cassettes) aligned along the robot installment area. When the hand approaches the substrate storage in order to take the substrate into or out of the substrate storage, the hand makes linear movement between an access start position, which is at a distance from the substrate storage, and a substrate placement position, which is in the area of the substrate storage. Here, a hand center line, which is oriented from the base of the hand to the distal end of the hand, overlaps an access straight line of the substrate storage (that is, the hand is immediately in front of the substrate storage). The access straight line is a straight line in a direction that is perpendicular to a front surface of the substrate storage and in which the substrate is taken in and out. The substrate transfer robot performs a similar access operation with respect to a substrate storage (processing chamber) of a processing apparatus, where the substrate is subjected to a predetermined kind of processing.